Botrytis cinerea is a fungal pathogen that infects almost all vegetable and fruit crops and annually causes $10-100 billion losses worldwide. With its broad host range, B. cinerea is a useful model for studying the pathogenicity of aggressive fungal pathogens. Many pathogens of plants and animals deliver effectors into host cells to suppress host immunity (H. Ashida et al., Curr. Opin. Microbiol. 14, 16 (2011); M. Rafiqi et al., Curr. Opin. Plant Biol. 15, 477 (2012); T. O. Bozkurt et al., Curr. Opin. Plant Biol. 15, 483 (2012); H. Hilbi, et al., Traffic 13, 1187 (2012)).
sRNAs induce gene silencing by binding to Argonaute (AGO) proteins and directing the RNA-induced silencing complex (RISC) to genes with complementary sequences. sRNAs from both plant and animal hosts have been recognized as regulators in host-microbial interaction (5-8). Although sRNAs are also present in various fungi and oomycetes, including many pathogens (9-14), it has not been clear whether they regulate host-pathogen interaction.